Personal computers and business computers are continually attacked by trojans, spyware, and adware, collectively referred to as “malware” or “pestware.” These types of programs generally act to gather information about a person or organization—often without the person or organization's knowledge. Some pestware is highly malicious. Other pestware is non-malicious but may cause issues with privacy or system performance. And yet other pestware is actual beneficial or wanted by the user. Wanted pestware is sometimes not characterized as “pestware” or “spyware.” But, unless specified otherwise, “pestware” as used herein refers to any program that collects and/or reports information about a person or an organization and any “watcher processes” related to the pestware.
The design and implementation of current and future pestware incorporates techniques that make the pestware difficult to identify, remove, or even to detect. These techniques, and likely future improvements to them, rely on patches, hooks and yet-to-be-discovered methods for modifying the behavior of a computer operating system itself. Such techniques render current detection tools ineffective by intercepting and altering the results of operating system queries from the tools that must rely on the dependability of operating system calls to return lists of running programs, file system and registry contents, for example.
Detection of pestware that uses these cloaking techniques is often ineffective by the real-time shields that existing anti-pestware applications utilize because these real-time shields begin execution after pestware has been able to execute and modify the operating system. FIG. 3, for example, illustrates the boot and operating system sequences that demonstrate the inability of user-mode services or applications to detect and prevent pestware (e.g., a Rootkit) that loads before them in a boot sequence. Periodic scanning for pestware is particularly ineffective because it leaves a window of time between scans in which pestware can execute and cloak itself. Accordingly, current software is not always able to identify and remove pestware in a convenient manner and will most certainly not be satisfactory in the future.